1. Field of the Invention
The invention relates to a supporting and tracking system for an endless belt upon which a cylindrical hay bale is adapted to be formed.
2. Description of the Prior Art
In balers of the type shown in U.S. Pat. No. 3,722,197 a windrow of hay is received on a lower endless belt which is driven oppositely to a plurality of upper belts. The hay is rolled onto itself between the upper and lower belts and is supported on the lower belt throughout the baling process. The lower belt also serves to convey the completed bale out of the baler onto the ground. Since the density and rate of flow of the hay are variable, it is inevitable that the load on the endless belt is not always uniformly applied, particularly as measured across the width (transversely) of the belt. The imposition of non-uniform loads on the moving belt imparts forces having transversely directed components tending to shift the belt away from a centered straight-line path of movement parallel to the baler centerline. This misalignment causes undue wear and premature failure of the belt.
The belt of the type in question is usually short in longitudinal extent relative to its width. As pointed out in U.S. Pat. No. 2,797,794 a problem with such belts is that large forces are required to maintain the belt in proper centered relation. In that patent the solution requires a resiliently restrained swivel-mounted assembly having side rollers 11 and a correction roller 6.
U.S. Pat. No. 2,391,249, 2,896,774, and 3,098,558 show belt-centering structure using swivel-mounted roller assemblies. However, the belts shown in these patents have the upper runs thereof troughed to reduce spillage of the material being conveyed and the belt centering structure is incorporated into the troughing structure.
The basic problem is to provide an effective and inexpensive system adaptable for long term, minimum-maintenance use, particularly in the difficult circumstances provided by field-going operation of a baler.